Event localization in a continuous scintillation detector using digital processing

The authors are currently developing a positron emission tomograph with multislice capability based on a single-slice prototype recently completed. For this tomograph they had to develop a two-dimensionally position-sensitive detector with several features not commonly found in similar detectors. The new multislice tomograph will consist of six detectors arranged in a hexagon. Each 2-D detector uses a NaI(T1) scintillator with a detector area of 110 x 470 mm and a thickness of 25 mm. The light emitted by the crystal is detected by an array of 30 square photomultipliers (50 x 50 mm) and the signals from the photomultipliers (PMT) are digitized as described below. Digitizing each photomultiplier signal provides greater processing flexibility for accurate determination of the location of an interaction within the crystal